Digestion
Mechanical digestion: physical breakdown of food molecules.
Chemical digestion: breakdown of macromolecules into building blocks.
Ingestion: taking in food molecules.
Excretion
Nitrogenous waste results from the breakdown of proteins.
Ammonia: toxic water-soluble nitrogenous waste.
Urea: non-toxic water-soluble nitrogenous waste.
Uric acid: non-toxic insoluble nitrogenous waste.
Nutrition
Macronutrients: molecules needed in large amounts by the body.
Carbohydrates
Lipids
Proteins
Micronutrients: molecules needed in small amounts by the body
Vitamins: organic molecules used as coenzymes.
Fat soluble vitamins: A, D, E, K
Water soluble vitamins: B, C
Minerals: inorganic molecules used as cofactors.
Amino acids
Animal
Ingestion
Digestion
Excretion
Porifera
filter feeders: collar cells pump water through body, screening out food.
collar cells digest, send nutrients to amoebocytes, which transport materials to other cells
water current removes undigested material
Cnidaria
capture prey with nematocysts. causes tentacles to move toward mouth, sweeping prey into gut.
cells lining gastrovascular cavity secrete strong enzymes to digest food. nutrients are absorbed by cells.
waste left in cavity leaves by same opening. other waste diffuses into water.
Platyhelminthes
scavenger, predator. mouth in middle of body, ventral side. extends pharynx out of mouth, sucks in food. passes to branched intestine.
nutrients absorbed into body through intestinal wall.
undigested food excreted through mouth and pharynx. chemical waste, excess water eliminated through flame cells connected to ducts running the length of the body.
Nematoda
anterior mouth
digestive tube
posterior anus
Annelida
take in soil through mouth as they burrow; sucked in by pharynx, passes through esophagus
stored in crop, ground up in gizzard, breaking up organic matter. food digested, absorbed by intestine
undigested food passes food out of anus. nephridia: get rid of nitrogenous waste.
Gastropoda
radula scrapes food
complete digestive tube
anus over head
Bivalvia
filter feeders: cilia on gills; beats to incurrent siphon. leaves through excurrent siphon.
mucus traps plankton, cilia beat to mouth. travels to stomach. absorbed in intestine.
waste leaves through anus
Cephalopoda
predator; capture with tentacles, radula, sharp beak to kill and eat.
complete digestive tube
waste leaves through anus
Echinodermata
tube feet obtain food; can open clam shells. turns stomach inside out.
enzymes in stomach digest clam in its shell. stomach withdraws and food is absorbed.
waste diffuses through skin gills
Crustacea
trap food with chelipeds, tear with maxillae and maxillipeds
food passes through esophagus to stomach: chitinous teeth grind up digestive fluids into body of prey
green glands remove wastes; undigested food passes through intestine and out anus
Arachnida
drink fluids that result from digestive fluids
external digestion: inject digestive fluids into body of prey
Malpighian tubules collect fluid, remove waste. waste travels to intestine
Insecta
labium, labrum hold food so mandible and maxillae can hold, tear, and cut. saliva moistens in mouth, stored in crop.
gizzard contains sharp chitinous plates to shred it, pass into stomach (midgut). gastric ceca mix food with digestive juices.
undigested food passes through hindgut (colon and rectum); Malpighian tubules in hindgut remove chemical waste. all waste leaves through anus
Chondrichthyes
specialized teeth to suit lifestyle
complete digestive tract
waste leaves through anus
Osteichthyes
usually carnivorous; jaws have teeth pointing inward. keep smaller fish, prey from escaping. tongue anchored, used to detect chemicals. mouth pharynx, esophagus.
stomach: digestion occurs in outlying ceca. liver and pancreas secrete digestive enzymes. intestine contains villi to increase surface area.
undigested food passes through anus. gills excrete nitrogenous waste. kidneys excrete nitrogenous waste, carried to urinary bladder.
Amphibia
tongue anchored in front; maxillary and vomerine teeth hold prey. alimentary canal complete: esophagus, stomach small intestine, large intestine. cloaca
gullet to stomach. glands secrete juices to break down food. nutrients absorbed into the blood stream in small intestine.
cloacal opening (hold waste from kidneys and bladder). carbon dioxide diffuses through skin. kidneys filter nitrogenous waste to produce urine.
Reptilia
may swallow whole; kill by injection or suffocation. jaws unhinge to allow mouth to open wide to swallow prey.
saliva begins digestion in esophagus, then in stomach
excrete uric acid to conserve water
Aves
no teeth or jaw bones. food passes from mouth to esophagus. crop stores and moistens food.
proventriculus of stomach secretes gastric fluids. gizzard crushes and grinds food. small intestine finishes breakdown, nutrients absorbed.
kidneys filter nitrogenous waste: form concentrated uric acid waste. ureters pass to cloaca.
Mammalia
specialized teeth. food enters mouth, begins digestion
stomach, intestine, accessory digestive glands
kidneys filter nitrogenous waste; undigested waste passes through anus.
Mouth
Begins the process of digestion by breaking food apart.
Contains salivary glands to produce saliva; lubricates food and begins starch digestion.
Teeth tear food into small pieces.
Tongue moves food into the pharynx.
Food is pushed into the esophagus, a long muscular tube leading to the stomach.
Stomach
Secretes gastric juice, used in the breakdown of proteins.
pH 2 to destroy foreign invaders.
Lined with mucus to protect the wall from digestion by gastric juice.
Small Intestine
Digests most food molecules.
Absorbs most nutrients.
pH 8
Lined with villi to increase surface area to improve digestion and absorption.
Large Intestine
Absorbs most water added during digestion.
Filled with symbiotic bacteria to aid in digestion.
Produces solid waste of undigested material.
Liver
Produces bile for the emulsification of fats.
Gall bladder stores bile.
Detoxifies materials received from the digestive tract.
Stores complex carbohydrates as glycogen.
Pancreas
Produces bicarbonate ions to neutralize gastric juice in the small intestine.
Secretes glucagon and insulin for glucose metabolism.
Digestion
Bile: used in emulsification of fats.
Gastric juice: contains hydrochloric acid for digestion of proteins.
Proteases: break proteins into amino acids.
Amylases: break down starch.
Excretion
Kidneys
filter metabolic waste from blood to produce urine
maintain osmotic balance of blood
Lungs
excrete carbon dioxide and water released by cellular respiration
Skin
excretes waste products in sweat
Plant Nutrition
Carbon source needed to produce organic molecules through photosynthesis.
Nitrogen: need for protein and nucleic acid synthesis; provided through soil in the form of nitrates or ammonia.
Phosphorus: part of ATP, nucleic acids, and phospholipids.
Magnesium, potassium, sulfur.
 

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